340 Vs 360

[frosty_the_punk]

Build that 318 with a 4 inch stroke and it will make more power than it did

This is the goal. I don't see the downside to this.

BUT you won’t have enough cylinder head on it. It’s IMPOSSIBLE.

Think about it.

The W2 head was developed in the early 1970’s and was for 330 inch drag stuff and 355 inch circle jerk stuff.

And for those displacements and rod to stroke ratios they were too small. They take an incredible amount of work.

So you tell me, how is that a good thing using a 4 inch stroke and being THAT cylinder head limited because I’m thinking if you are starting with a 318 you won’t front for W2 heads?

You will be severely RPM limited unless you run outrageous cam timing.

I get what you're saying, there are limitations to rpm which increase with displacement.

But I'd rather have more horsepower with less RPM than more RPM with less horsepower.
Because horsepower is performance.

Here is an example. This may help you understand.

In 2000 I built a 408. It had fully ported Edelbrock heads and a fully ported Strip Dominator. IIRC it was 10.8:1 but it could have been a skosh higher. It had a custom Cam Motion hydraulic roller that IIRC was in the low 240’s @ .050 and was in the low to mid .500’s for lift. It had a 750 Holley and 1 7/8 headers.

With you so far.

And guess what? At 5200 it was OVER. Used up. No more. It’s tongue was out and bloody.

Is there a specific reason why this is a problem?
Besides your personal appreciation for an engine's ability to turn RPM?

We could have used more cam but then it would have needed more RPM (which is taboo)

Isn't "needing more rpm" the thing that happens when you have a smaller engine, too?

and it would have lost some bottom end (another fallacy).

It made 545 HP and I forget the TQ because who cares? It was close to the HP or maybe it was more.

"Who cares?"
About torque?
I think torque is something that lots of people would consider to be relevant when judging an engine's performance.
Not the only thing, but it is relevant.

Here‘s the real pisser. I would have built it with a 3.58 stroke (or maybe the 3.79 stroke as either would have been better than the 4 inch arm)

"Better" seems to be a bit subjective.
I think it would have made less horsepower with the smaller displacement, which is difficult for me to consider as being better.

and instead of the anemic 5200 RPM I would have turned the 365 inch (3.58 stroke) 7200 or the 387 incher (3.79 stroke) 6500ish and I could make the same 545 HP but at the higher RPM

It's my opinion that it would have taken a "bigger" cam or some other kind of top end optimization to match the hp output of the larger engine.

I have never seen a situation where an increase in displacement didn't pickup at least a few ponies

and the smaller engine would kick the living **** out of the 408. Every. Single. Time.

If they had both made the same 545hp, and the gear ratios were then optimized for each. I respectfully disagree.

I think they'd perform comparably.
But I am open to a discussion as to why 545hp @ 7200rpm is going to provide faster acceleration than 545hp @ 5200rpm in a car of equal weight

Understanding the math of it is relatively simple. Dealing with the facts is the hard part evidently.

I'm not saying you're wrong.
But would you be able to provide an example of a situation where a decrease in displacement resulted in a real world measurable performance gain?

 

[frosty_the_punk]

Here is 2023 day 1. There are links to day 2 and the rest of them right there.

Wow, that video is 8 hours long.

I'm sure it's full of great info, but for the purposes of trying to understand what you're trying to communicate to me in these forums, Is there a particular part you could refer me to which is most relevant to the topic at hand?

 

[Bakerlite]

 

[frosty_the_punk]

You need to look at high end builds but it's not necessarily in what parts they use but they do with them, here one build that fits the bill an engine master competition motor not the show but an actual competition, it's a 360 bored to 371 making 515 hp @ 6000 rpm's and 495 lbs-ft @ 4800 rpm and over 400 lbs-ft 2500-6500 rpm, that's the torque of larger like a 408, and hp at reasonable rpms. Pretty sure this is one of the builders on here.

371ci Mopar Small Block - Popular Hot Rodding Magazine

The judging for the EMC for that year was based on three consecutive pulls from 2500-6500RPM.
With a cubic inch factor added in to take into consideration the variations in displacement between competitors.

If you're trying to make as much "average horsepower from 2500-6500 per cubic inch" which is what this competition is comparing .. then sure. Limit your cubes to get the powerband where need it to win the dyno trophy.

That's a heck of a potent 371ci engine, But with a 4" crank it would end up at 414ci and would've made more overall horsepower at a bit lower RPM

And horsepower is what gets you across the line before the guy in the other lane.

 

[rumblefish360]

Piston speed, Would you use a cast cranks for 10,000 rpm motor even a 8,000 rpm ?

Good morning! Sipping the first cup of coffee….

It’s not would I or not but can it be done.
The short answer is yes it can be done.
To answer your direct question to me, no I will not be using a cast crankshaft. Current cast cranks in house need machining while the forged ones are ready to go.

If your building above 1.3 lbs-ft per cid your doing something right, 1:15-1.29:1 is decent average guy above 1.2:1 should be proud.

Gotta agree there! Though the pride level …. Dangerous word pride.

Nope Justinp61

 

[rumblefish360]

Good morning, first cup of coffee going down!

A Ritter block is about 4k. And you know what? So is the equivalent SBC or Ford block. You can buy the lower grade blocks from Dart and such but to compare that block to a Ritter requires one to compare apples to apples. The day of the 2k SBC are over and 4k (or damned close to it) is what a quality SBC or Ford block costs.

Thanks for the cost info and the rest seems to fall into place of what you say …. “cheap MoPar guys…..” 4K is an expense I can not justify right now in my head to fully take advantage of, if such a block.

The purpose of the rods is RPM. Isn’t that what we are discussing?

I get that, yup. Discussing? The whole topic is 340 vs 360. In reality, the whole thread is a mental masturbation. As far as con rods by it’s self, I only asked you a single question on it.

You can buy a QUALITY connecting rod for under 500 bucks. Less than that if you shop around. I bet I can find a good 4340 H beam rod with 7/16 cap screws for 300 dollars. You can’t rebuild a set of stock rods for that, and they will STILL be 1018 steel with 3/8 bolts and nuts.

How far would you take that interns of HP?

You can easily get a crank for under 1k that will take all the abuse you can give an NA engine. I beat the living **** out of stock cranks at 8500 and never broke one. And I was magnafluxing my stuff at least once a year. I also ran aluminum rods and didn’t use a rubber band damper.

I wonder if 273 read that?

Chrysler shaft rockers have a huge weak spot and there isn’t much you can do about it. And that’s the 5 3/8 mounting bolts. The Chevy guys get EIGHT 7/16 bolts to secure the rockers. That’s a big deal when you get to 9k and above. Those 5 bolts move around like a wet noodle.

The excuse is that it takes exotic or high end parts to make RPM worth doing just isn’t true, unless you are married to OE parts.

And there it is! Let’s move away from the OEM parts! Get into a real power potential part. Now the average guy is saying, “Wait! What is this costing me?!?!”

For you, just you, what parts make high end and what parts make exotic? When does exotic become common place?

If that’s the case then what are we discussing? Are we talking about making horsepower or just mentally masturbating about things some of us don’t have any experience in?

In risk of repeating….

The whole thread is a mental masturbation of which is better,
340 vs 360.
It’s inevitable that such discussions turn into race building threads examining and exploiting and nit picking and splitting hairs on every last item as well as the theoretical and extreme.

Most here haven’t turned a crank past 6800. But will comment anyway. In short, basically speaking, the whole thread is a pile of bullshit. Why? Because 99% of anyone reading this will never go there and those that did, well, great for them.

Truly, how many people will this thread help?

The thread should be retitled,
“340 vs 360, an exercise in mental masturbation!”

 

[frosty_the_punk]

.Chrysler shaft rockers have a huge weak spot and there isn’t much you can do about it. And that’s the 5 3/8 mounting bolts. The Chevy guys get EIGHT 7/16 bolts to secure the rockers. That’s a big deal when you get to 9k and above. Those 5 bolts move around like a wet noodle.

Just out of curiosity, what are your thoughts on the rigidity of this engine lift plate... which is only held on by four 5/16" bolts?

Is it as stable as a chevy rocker arm, or would it need a lot more bolts?

 

[mopowers]

Has anyone changed anyone else's mind yet?? News flash - you guys are wasting your time.

 

[rumblefish360]

Mental masturbation, thread!

 

[justinp61]

Hey, at least Uncle Tony is getting a break!

 

[Rat Bastid]

This is the goal. I don't see the downside to this.


I get what you're saying, there are limitations to rpm which increase with displacement.

But I'd rather have more horsepower with less RPM than more RPM with less horsepower.
Because horsepower is performance.

With you so far.

Is there a specific reason why this is a problem?
Besides your personal appreciation for an engine's ability to turn RPM?

Isn't "needing more rpm" the thing that happens when you have a smaller engine, too?

"Who cares?"
About torque?
I think torque is something that lots of people would consider to be relevant when judging an engine's performance.
Not the only thing, but it is relevant.

"Better" seems to be a bit subjective.
I think it would have made less horsepower with the smaller displacement, which is difficult for me to consider as being better.

It's my opinion that it would have taken a "bigger" cam or some other kind of top end optimization to match the hp output of the larger engine.

I have never seen a situation where an increase in displacement didn't pickup at least a few ponies

If they had both made the same 545hp, and the gear ratios were then optimized for each. I respectfully disagree.

I think they'd perform comparably.
But I am open to a discussion as to why 545hp @ 7200rpm is going to provide faster acceleration than 545hp @ 5200rpm in a car of equal weight

I'm not saying you're wrong.
But would you be able to provide an example of a situation where a decrease in displacement resulted in a real world measurable performance gain?

I gave you two examples of smaller engines being quicker and faster even at the same horsepower.

Think about this. I have to make the math easy because I don’t feel like doing a bunch of math today.

Lets say you have 1320 feet to get the job done. But it doesn’t matter because any length of course will work. Or even on the street. That’s why God gave man the brains to make transmissions. Never overlook that fact.

You’ve got 1320 feet. And your car does 10 flat. At let’s say…6000 RPM. That means you have 100 RPM per second. You divide that by two (because the crank has to turn twice to make one cycle) and you get 50 firing cycles per second. You following this?

You make power by firing the cylinder. Even at the same horsepower.

In the above example for a 10 second run you get 500 firing cycles during the run. That’s it. In fact, the crank only turns 1000 times!!!!!! That’s not many times is it.

Now let’s say that we change the engine up so that it makes the exact same HP but it does it at 7500 RPM. That’s 125 RPM/Sec. That’s 25% more RPM/Sec that at 6000 RPM.

That means you have the crank turning 1250 times during a 10 second run. Which is 650 firing cycles during the same run. You have 150 MORE times that the cylinder is making power.

And you say so what? It’s still running 10 flat. Maybe, but the car should go quicker IF you tune the chassis and converter for the higher RPM and more firing cycles.

Thats at the same HP. You can’t take gearing and converter out of it because it matters.

Thats why I can say I could have built the same engine as above with LESS stroke and MORE RPM and gone quicker and faster with less displacement.

Of course, this is somewhat simplified because the RPM used is peak and not the average RPM a going down the track.

Obviously you launch at an RPM lower than 6000 or 7500 RPM, and you have RPM fall back at the gear change. But the fact remains that RPM will INCREASE displacement!!! It sure does.

Every time you fire the cylinder you are displacing 1/8 of your total CID. If you fire the cylinder more times you are effectively increasing the displacement.

It‘s amazing how so many discount or even ignore gearing and gear ratios. It’s a simple concept.

Just like a longer wrench will give you more leverage than a shorter wrench, lower gearing gives you more leverage than a longer stroke will.

 

[Rat Bastid]

Wow, that video is 8 hours long.

I'm sure it's full of great info, but for the purposes of trying to understand what you're trying to communicate to me in these forums, Is there a particular part you could refer me to which is most relevant to the topic at hand?

That’s why I said look for the sections where they discuss the EFI University engine build. There are several parts to it. It has some cools stuff like in chamber combustion analysis and such. Plus it covers what we are discussing.

 

[Rat Bastid]

Good morning, first cup of coffee going down!

Thanks for the cost info and the rest seems to fall into place of what you say …. “cheap MoPar guys…..” 4K is an expense I can not justify right now in my head to fully take advantage of, if such a block.

I get that, yup. Discussing? The whole topic is 340 vs 360. In reality, the whole thread is a mental masturbation. As far as con rods by it’s self, I only asked you a single question on it.

How far would you take that interns of HP?

I wonder if 273 read that?



And there it is! Let’s move away from the OEM parts! Get into a real power potential part. Now the average guy is saying, “Wait! What is this costing me?!?!”

For you, just you, what parts make high end and what parts make exotic? When does exotic become common place?

In risk of repeating….

The whole thread is a mental masturbation of which is better,
340 vs 360.
It’s inevitable that such discussions turn into race building threads examining and exploiting and nit picking and splitting hairs on every last item as well as the theoretical and extreme.

Most here haven’t turned a crank past 6800. But will comment anyway. In short, basically speaking, the whole thread is a pile of bullshit. Why? Because 99% of anyone reading this will never go there and those that did, well, great for them.

Truly, how many people will this thread help?

The thread should be retitled,
“340 vs 360, an exercise in mental masturbation!”

It’s only mental masturbation if you can’t keep up or you can’t differentiate between cost and value.

Think about it. You and all the “street guys” are the ones who struggle with what a race engine is.

You have to post your defintion of “race” if you want to go down that rabbit hole. If you think 7500 is race RPM you are 30 years behind.

Look at how many threads there are about the junk main girdles. That garbage wasn’t made because someone was sitting around, bored. There is a PROBLEM. And the problem is you can buy more horsepower cheaper than ever.

How many guys buy a stroker kit? Damn near everyone. Unless you are as cheap as they come, you get a 4340 non twist forged crank (I’m old enough to remember when the non twist forging was a big deal…now no one mentions it because it’s so commonplace) and a set of 4340 rods with 7/16 cap screws. And you get a set of pistons that 30 years ago would have been “race only” stuff and even those things are obsolete because most of those pistons still have the 1/16, 1/16, 3/16 John Deere ring pack. They should ALL get 1mm ring packs but that’s still too “racey” even though your average Honda has a 1mm ring pack.

Cams and induction have gotten better along with cylinder heads.

And yet, with all that power available the VALUE of an aftermarket block is poo-poo‘d as a needless expense when in fact you waste money dumping all that money into a passenger car block that was designed and developed for 5000 RPM maximum and what?? 320 HP?

These blocks bend and twist and flex and ring seal goes straight to hell. A main girdle won’t fix that. You have to run wider than needed bearing clearance because the block is not much better than a slightly under done noodle. So you have to give the flexing block more clearance so it doesn’t grab a bearing. A main girdle won’t fix that either.

It comes down to value and durability. Running a stock block and trying to make power is an exercise in pissing into a fan.

Ive taken apart hundreds of 500 plus HP engines over the years and not one single stock block wasn’t showing signs of distress.

The main bearings are showing odd wear. The main line is no longer round. Or straight. The bores are iffy at best. The head gaskets show sings of barely sealing up because the decks are so thin they move around like a cheap ***** on coke at a disco.

So it’s not mental masturbation. It’s about learning and unlearning.

Learning what new technology allows not only in power but in durability. And unlearning nonsense like main girdles and aftermarket caps (the caps are great and strong but the block is still 5 day old oatmeal) and filling the block and all that monkey motion that doesn’t little or nothing.

Making power and stepping over donuts to grab dog turds is counter productive. And costly.

 

[Rat Bastid]

Just out of curiosity, what are your thoughts on the rigidity of this engine lift plate... which is only held on by four 5/16" bolts?

Is it as stable as a chevy rocker arm, or would it need a lot more bolts?

View attachment 1716038121

Come on dude. Now you just want to argue.

To compare that lift plate to eight rocker arms working on eight valve springs at 50 or 60 times a second is just stupid.

Set the engine on the ground and then jerk it straight up two feet and then stop it. Then slam it down as fast as you can until it barely touches the floor and see how long those little bolts hold up. It won’t be long.

 

[Rat Bastid]

Hey, at least Uncle Tony is getting a break!

Uncle Tony doesn’t have the money or the skill to build anything. He can’t run a mill or a lathe (or he’d figure out a way to get that at the shop) let alone run any automotive machine tools with any accuracy.

Big difference between a machinist and a play engine builder.

 

[Rat Bastid]

Has anyone changed anyone else's mind yet?? News flash - you guys are wasting your time.

If you can’t keep up, feel free to move on rather than tell everyone else what to do.

 

[mopowers]

feel free to move on rather than tell everyone else what to do

Did I?

You guys remind me of my ex - arguing for the sake of arguing. This site is great for a good laugh.

 

[Rat Bastid]

Did I?

You guys remind me of my ex - arguing for the sake of arguing. This site is great for a good laugh.

Laugh all you want. Smart people set aside their preconceived thinking and learn.

I can go to any track in the country and look at slow junk and you can bet it was built by interweb concensus.

 

[318willrun]

See if you can watch this and not think of a FABO thread ...

 

[Rat Bastid]

See if you can watch this and not think of a FABO thread ...

Did you ever notice the guys that build slow stuff never add anything?

 

[318willrun]

Did you ever notice the guys that build slow stuff never add anything?

scripture... "a living dog is greater than a dead lion"

In car talk : a 318 2bbl that lays a black mark and runs 15.98 is greater than a 550 hp killer motor that will never run, drive, or make a pass at the track.

 

[Rat Bastid]

scripture... "a living dog is greater than a dead lion"

In car talk : a 318 2bbl that lays a black mark and runs 15.98 is greater than a 550 hp killer motor that will never run, drive, or make a pass at the track.

In your world maybe. I take my junk to the track. And drive it on the street.

If you care about a burnout then we don’t hang in the same circles.

 

[crackedback]

Just out of curiosity, what are your thoughts on the rigidity of this engine lift plate... which is only held on by four 5/16" bolts?

Is it as stable as a chevy rocker arm, or would it need a lot more bolts?

View attachment 1716038121

More likely to rip the threads out of the aluminum than kill the bolts themselves. Tensile stength of ONE 5/16 grade 5 fastener is more than sufficient to lift most engines and there are 4 of them. The bolts are in stretch, a rocker stud has forces applied differently.

Pro tip... NEVER use bolts to attach the lift plate on an aluminum intake.

 

[318willrun]

In your world maybe. I take my junk to the track. And drive it on the street.

If you care about a burnout then we don’t hang in the same circles.

What did it run ?? Love to see the ET slip I say that genuinely, not sarcastically

 

[Rat Bastid]

What did it run ?? Love to see the ET slip I say that genuinely, not sarcastically

LOL.